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y, Dares rnraperauwr and ~ for the Pamir and Ad/aemr Arear Groundwater Barren Member well B-32 exhibited virtuaAy no response to seasonal influences which indicates no apparent connection to surface Some groundwater wells exhibited slightly changeA recharges. conditions in some instances and the subsidence monitoring deep wells showed some influence from • "F"-seam wells SOM-2, and SOM-16 show mining. Overall however, the wells remained fairly no seasonal or amual fluctuation and have constant compared to previous years. Most notably, little or no surface water connection. the 1991 data indicate: • Barren Member wells SOM-13 and SOM~0 • Refuse area wells SG-1 and GP-1 continued have shown seazonal variations in previous to show lower levels than in years previous to years. During 1987, SOM~0 showed very 1987. This is due to persistent lower precipi- little or no response to seasonal fluctuation ration patterns. while SOM-13 was similar to previous years. Since 1988, neither well haz shown a response • Refuse area wells GP-3 through GP-5, az in to seazonal fluctuation. previous years, contained no water. • The shallow subsidence monitoring wells, • Barren Member well 38-H-1, az previously SW-1 through SW~i, were generally the same described, waz affected by subsidence. This az in previous years. well haz since recovered to pre-mining water levels' Lower Refuse Pile • Barren Member well 38-H-2 continued to • have casing blockage problems which oc- curred after it was installed. Very little data were collected at this well due to [he prob- lem. The casing was apparently damaged by subsidence az described earlier in this section Barren Member well 38-H-3 provided no useful well data in 1991. Moisture problems with the casing and later communication with the mine workings, probably caused by subsi- dence, precluded the determination of water Levels. During 1991, mine development waste from the underground mining operations was placed in the lower refuse pile. The lower refuse pile was per- mitted for permanent disposal oCsome 1.7 million cubic yards of mine development wazte, coal processing wazte, and sediment pond cleanout material. In 1991 approximately 54,900 tons (61,300 cu. yd.) were placed in the lower refuse pile in the phaze N area. Table 7 shows the 1991 sampling results from monitoring well GP-1 az well az baseline data Table 7 Comparison o[ GP-1 Baseline and 1991 Sampling Results, West Elk Mine Sampling pH Conduct. TDS Temp. Fe Mn Date Turbidity (units) (µmhos/cm) (mg/L) (°C) (mg/L) (mg/L) 08N8B5 048 7.5' 990 566.0 10.1 <0.02 0.21 08/OSBS 048 7.5 990 526.0 I0.0 <0.02 0.21 (Dup) 10/10/85 054 -- 693 870.0 7.5 <0.02 0.05 `OSIW/91 008 7.1 958 642 12.2 0.33 0.03 06/11/91 010 7.5 779 622 10.0 0.16 0.02 09/19/91 , <193 6.7 898 444 8.8 X81.0; ~ 3.02> • 12